1. Field of the Invention
The present invention relates to a technology for generating song reproduction instruction information for use, for instance, in a device that is capable of reproducing audio.
2. Description of the Related Art
In recent years, small-size, lightweight, portable audio players have become widespread. Therefore, people can now listen to various songs (various types of music) in unprecedented situations. For example, many people carry a portable audio player and listen to music while walking outdoors or while jogging, walking, or playing any other sport for health maintenance, heath enhancement, or dieting purposes.
When the tempo of a reproduced song matches the tempo of user motion, the user realizes a sense of unity between motion (exercise) and song (music). For example, the user motion is walking, jogging, or other exercise. In this document, the tempo of walking, jogging, or other exercise or motion is hereinafter simply referred to as the exercise tempo. Even when the exercise tempo of the user suddenly changes or fails to match the tempo of a reproduced song, a certain device such as detecting the user's exercise tempo and changing the tempo of the reproduced song in accordance with the exercise tempo has been devised to provide.
In this document, the terms “song (music) tempo,” “song (music) reproduction tempo,” and “song tempo” refer to a speed at which music data is reproduced and, more specifically, refer to the number of beats per minute (BPM). To be more precise, the user's exercise tempo is a motion (exercise) speed. If, for instance, the user's motion (exercise) is walking or running, the exercise tempo refers to the number of steps per minute. If the user's motion is jumping, the exercise tempo refers to the number of jumps per minute. In any case, the exercise tempo refers to the number of countable minimum motion units per minute.
A device disclosed by Japanese Patent Laid-open No. 2005-156641 (hereinafter referred to as Patent Document 1) uses a detector, which is attached to the user's body, to determine the pace of walking or other exercise from vibration that accompanies a motion (exercise) or step data about walking, and changes the song reproduction tempo in accordance with changes in the pace. The use of this device makes it possible to do a continuous exercise comfortably or do an exercise efficiently to reproduced songs.